Monitoring the prevalence of thyroid disorders in the adult population of Northeast Germany

Abstract Background Only a few studies like ours have investigated the effect of long-term stable iodine supply on thyroid disorders in a historically iodine-deficient population, but not with a long follow-up time of 10 years. Methods Data were derived from two independent population-based cohorts of the Study of Health in Pomerania (SHIP-0 [1997–2001] and SHIP-TREND [2008–2012]) comprising 4308 and 4420 subjects, respectively. Diagnosed thyroid disorders were assessed. Thyroid gland dimensions were examined by ultrasound. Levels of serum thyrotropin (TSH) and autoantibodies to thyroperoxidase (anti-TPO Abs) were measured from blood samples. Results Median urinary iodine excretion levels decreased from 123.0 μg/l to 112.0 μg/l (p = <0.001) between 2000 and 2010. The prevalence of known thyroid disorders increased from 7.6 % [CI 6.9–8.5] to 18.9 % [CI 17.6–20.1] and of thyroid medication use from 6.2 to 11.1 %. The prevalence of goiter decreased from 35.1 to 29.4 % (p = <0.001), while the prevalence of positive anti-TPO Abs decreased from 3.9 to 2.9 % (p = 0.022). Median serum TSH levels increased from 0.69 mIU/L to 1.19 mIU/L (p =